Via Aqua 302 & 305 aquarium and fountain submersible water pump.

here's a link. We use the 302 pump in a 10 gallon tub to drip for 6 plants.

FastGardens.com : 6 plant drip system

Here is the system we bought first and then made our own for half price. The pump could be put in a rez and feed 5 gallon buckets that gravity flow back to rez. The possibitlities are endless Throw an air stone in and you can cut the punp off when roots are in the rez water.